| Objective1. To determine the optimal dosage of Streptozotocin (STZ) inducing non human primates (Rhesus monkey) diabetes model;2. To investigate the impact and correlation of liver hemodynamic and hepatorenal function by implanting various dosage of micro-capsule either via hepatic artery or portal vein.3. To evaluate and compare the efficiency of treatment of diabetes in Rhesus Monkey using neonatal pig islets transplanted through hepatic artery and portal vein, which would benefit further clinical application.Methods1.25 heathy male rhuses monkeys were catergorized to A(n=5), B(n=5) and C(n=15) groups,which intravenously adminstrated 125mg/kg,75mg/kg,50mg/kg of STZ, respectively. The metabolic reactions, such as blood glucose, C peptide, IVGTT were measured at pre,0-48 hours and 1-16 weeks after STZ adminstration and the correlation of hepatorenal function and dose response were evaluated. Accoding to the criteria of diabetes model, the blood glucose are equal or greater than 11.1mmol/l consistently, the safe and optimal STZ dosage to induce diabetes in rhuses monkey were determined.2.38 healthy male dogs were divided into three groups. Group A (n=20) further subdivided into four groups, A1 implanted 8000 microcapsule/kg, A2 implanted 16000 microcapsule/kg, A3 implanted 32000 microcapsule/kg and A4 implanted 48000 microcapsule/kg via hepatic artery; while Group B (n=15) subdivided into three groups, in brief, group B1,8000 microcapsule/kg, group B2,16000 microcapsule/kg and group B3,32000 microcapsule/kg were implanted via portal vein; group C (n=3):as control group, transplanted the same volume of heparin saline. Portal venous pressure, diameter and blood flow rate of portal vein were measured, the correlations of dosage of Microcapsule, Portal venous pressure and blood flow rate were analyzed. 3. Rhesus monkey diabetes model induced by STZ were categorized into three groups, group A (n=6):transplanted via hepatic artery; group B (n=9):transplanted via portal vein and group C (n=3) as control group. Blood glucose, C peptide, IVGTT and hepatorenal function were monitored at pre,1 day,1,4,8,12,24,26,32 and 40 weeks post transplantation. The function of transplanted islet grafts was evaluated. Samples of liver and pancreas were collected and stained with Insulin and Glycogen after animals sacrificed.Results1. The successful rate of STZ induced diabetes in Rhesus monkey on 125mg/kg, 75mg/kg and 50mg/kg groups were 2/5 (40%),3/5(60%) and 13/15(86.67%) respectively. For all developed diabetes rhesus monkeys,48 hours after administration of STZ, blood glucose and C peptide were presented as typical tri-phase reactions. Both 125mg/kg and 75mg/kg group, their liver and kidney functions were markably damaged, especially liver functions, ALT and AST in blood lever were consistent elevated dramatically. In 125mg/kg group, the ALT and AST lever were as high as 10235.38±1745.35 nkat/L and 3759.09±246.72 nkat/L. In 75mg/kg group, the ALT and AST lever were as high as 10002.00±848.50 nkat/L and 4407.55±3317.33 nkat/L. In addition, higher mortality rate occurred in these two groups. However, in 50mg/kg group, the rhesus monkeys developed stable and irreversible diabetes without notable impact of liver and kindey function.2. Incresing dosage of microcapsule via portal vein transplantation (microcapsule from 8000/kg to 32000/kg), the portal vein pressure was increasing, blood flow rates were diminishing and the diameter of main branchs of portal vein expanded. There were four animals died at 48 hours after implanted 32000/kg of microcapsule due to Zahn infraction occured in liver as quickly decreasing blood flow and incresing portal vein pressure. However, implantation via hepatic artery, incresing dosage of microcapsule (microcapsule from 8000/kg to 48000/kg), didn't influence the hemodynamics of portain vein and liver function, no mortality occurred. Compare to portal vein implantation, more microcapsules can be implanted via hepatic artery without impact liver function and hemodynamics of portal vein. 3. The islet grafts, which transplated either via portal vein or hepatic artery, can survive long time and maintain functional. The dosage of exogenous insulin administrated in both Groups (hepatic artery group A and portal vein group B) were decreased to 59.53% and 48.39% respectively, comparison to pre-transplantation. Moreover, exogenous insulin administration discontinued since 15 weeks of post-transplantation and lasted for 100 days in Group A3,12 weeks after transplantion and lasted for 20 days in Group A6,25 weeks after transplantion and lasted for 40 days in Group B1. There were no significnat diffirences between Group A and B in dicresing dosage of exogenous insulin administration. Both Groups had low level of human serum C peptide(<0.2μg/L), whereas the level of pig serum C peptide was increasing gradually, reached their peak value at 8 and 16 weeks respectively (0.56±0.18μg/L; 0.61±0.11μg/L), which suggested that the transplanted islets grafts were survival and functional. There was no significant difference in pig serum C peptide lever between Group A and B (P>0.05). However, the surgical procedure through portal vein transplantation was more likely arousing bleeding, blood coagulation and portal hypertension. Nevertheless, it was relatively easier and safer via hepatic artery transplantation when animal were kept properly position and calm down for a while after transplantation.Conclusion1. Small dose of STZ,50mg/kg, is able to induce non human primate (Rhesus monkey) diabetes irreversibly without damage liver and kidney function and this model is reliable and useful for research of diabetes.2. Compare to the portal vein, transplantation via hepatic artery can accommodate more islet grafts with few side effects of hepatic hemodynamics and hepatorenal function.3. The procedure of transplantation via hepatic artery is safer, easier, with fewer complications, compared with transplantation via portal vein.4. Either transplantation via hepatic artery or portal vein, the xeno islet grafts can survive Long time and maintain functional. There is no significant diffirence on reversing symptems of diabetes between both transplatation passways.
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